Booming Castor Royal

Imitative-onomatopoeic origin — present-participle of boom, sharing root with Dutch bommen. As a color modifier, booming implies a saturated-and-loud-and-confident quality where the hue announces itself with full visual amplitude. Sits at the bold-and-resonant end of the grid, parallel to resounding and thunderous.

Greek Κάστωρ, Gemini-twin-and-horseman. As a color modifier, castor implies a Gemini-twin-and-mortal-brother quality, the visual register of Gemini-Castor-and-Pollux-twin hand-Gemini-twin-and-mortal-brother Gemini-Castor-and-Pollux-twin-and-Argonaut castor-and-Gemini-twin-and-mortal-brother surfaces under Gemini-Castor-and-Pollux-twin-and-Argonaut spring-Gemini-and-Bortle-1-sky stellar-twin-light. Sits at the modifier-and-cosmic end of the grid, parallel to pollux and spica in usage.

The blue of European royal court dress and regalia from the late seventeenth century forward — the color of British peers' robes, French royal sashes, the lining of the crown-jewel cases. The color refers to a saturated, slightly violet-shifted blue with the matte finish of velvet or melton wool dyed to maximum intensity: deeper than cornflower, warmer than ultramarine, with the heraldic weight of a color reserved for monarchs and the official Crown.